Referring to FIG. 1, a networked storage platform 100, such as an EMC Symmetrix® Storage Array, can be used by an enterprise or other organization to maintain and protect large amounts of data which can be accessed via a communications network 102. The storage array includes at least one standardized network interface to support IO operations via the network 102. For example, the interface may support a storage protocol such as SCSI or NFS over a network protocol such as Fibre Channel (FC), Ethernet, or Infiniband. Data may be stored in various tiers of storage, each associated with various different physical storage devices, groups of which may have different performance characteristics. Redundant copies of data may be maintained within the storage array, and the storage array may be mirrored by another storage array. Various other features which are known in the art distinguish a typical network storage platform from other storage devices.
The operations performed within the storage platform to support data maintenance, protection and IOs are hidden from other devices. From the perspective of a host device 104, such as a server, an IO appears to be a local operation because, e.g., a SCSI command that would be used to access local storage is encapsulated, sent to the storage platform, de-encapsulated, and processed. The host is unaware, for example, of where the data is stored by the storage platform, or how the data is protected. However, the handling of data by the storage platform can affect performance of the host. In the example of an Internet transaction a user 106 initiates the transaction by communicating with the host device 104. The host device operates instances of applications created to support particular types of transactions. Operation of the applications may require access to data maintained by the storage platform 100. Consequently, IO operations take place between the host device and the storage platform in support of the application which is operated to support the transaction initiated by the user. If these IO operations include retrieval of data from relatively slow storage tier then latency increases. Furthermore, some latency can be expected from the network.